Thirty to 40 people who attempted to smash the door of a downtown store ran off after Palo Alto police officers responded to the scene over the weekend, the department said on Wednesday.

The group of people who arrived in 20 cars attempted to break into The RealReal luxury consignment store on University Avenue on Sunday night (Nov. 21), but a call from a private security guard and an immediate response from officers led them to flee empty-handed, police said in a press release. Officers stopped one of the cars as it left the scene and arrested its two occupants.

The security guard called police dispatchers around 11:20 p.m. to report the in-progress burglary attempt at the store. The guard, who is employed by the business, saw the cars arrive and the group attempted to break the front door.

The would-be burglars smashed the front glass door, but it held firm and the group was not able to make entry into the store. The security guard reported that the men and women wore face coverings, police said.

An officer located one of the cars, a green 2017 Ford Escape SUV, which had its headlights off and no license plates, on Willow Road at Chester Street in Menlo Park and detained two occupants without incident. Inside the vehicle, police located at least $15,000 worth of stolen property from another The RealReal location, police said.

The clothing was still on hangers; price tags and security sensors were attached. Officers also found a hammer, police said. The stolen property had been taken in a similar burglary at The RealReal store in Larkspur earlier in the night, investigators learned.

The two detained women allegedly traveled with the caravan of thieves and were at the scene when the group attempted the Palo Alto break-in. They fled when they heard police responding. The women had in their possession about $15,000 in merchandise believed to have been stolen from The RealReal in Larkspur.

No video surveillance of the attempted burglary is available for release, police said.

Investigators are working in close collaboration with detectives from the Central Marin Police Authority on the two cases.

In the Larkspur burglary, Central Marin police said officers were dispatched to the shop after a 9:13 p.m. call from a security guard reporting the sudden arrival of 40 people. Police said officers arrived within two and a half minutes, but the group had already fled the scene after smashing windows, breaking in and burglarizing the store.

Detectives are also continuing the Palo Alto investigation to identify the other persons involved and to determine if there are any connections with similar crimes in the Bay Area.

Police booked the two women, a 20-year-old from Richmond and 21-year-old from Vallejo, into the Santa Clara County Main Jail on suspicion of attempted commercial burglary and conspiracy, both felonies.

A group of seven individuals swiped $50,000 worth of handbags from the RealReal in Palo Alto in June while the store was open.

"With similar recent crimes throughout the Bay Area, including past incidents of organized retail theft of open businesses occurring in Palo Alto, officers have stepped up patrols both during the business day and overnight in retail areas of Palo Alto. Police thank the security guard in this case for promptly calling for help, as that prevented the burglary from being completed," the department said in the press release.

Police encourage anyone who witnesses suspicious behavior in and around retail establishments in Palo Alto to call the department's 24-hour dispatch center at 650-329-2413, or 911 if it is an emergency.

Anyone with information about this incident is asked to call the dispatch center. Anonymous tips can be emailed to paloalto@tipnow.org or sent by text message or voicemail to 650-383-8984. Tips can also be submitted anonymously through the police's free mobile app, downloadable at bit.ly/PAPD-AppStore or bit.ly/PAPD-GooglePlay.

Editor's note: Palo Alto Online's policy is to withhold the names of those arrested for most crimes until the District Attorney has determined there is sufficient evidence to file charges in the case. Read our guidelines.